Heat pump apparatus and method for controlling regulating valve

ABSTRACT

It is aimed to provide a heat pump type hot-water supply outdoor apparatus that can control a temperature of a compressor shell, according to a water temperature of a water circuit and a temperature of the compressor. A heat pump type hot-water supply outdoor apparatus includes a refrigeration cycle including a compressor, a water-refrigerant heat exchanger, an expansion valve, and an air heat exchanger, a water jacket that is arranged on the shell of the compressor and connected in the middle of a branch water circuit branching in parallel to a main water circuit which starts from a hot water storage tank and returns to the hot water storage tank through a water-refrigerant heat exchanger, a water flow valve that is connected between a branch and the water jacket and regulates the quantity of water flow, according to a control signal, a shell temperature detection sensor that senses a temperature of the shell of the compressor, a water temperature sensor that is installed in the vicinity of the branch and senses a temperature of the water flowing out of the hot water storage tank, and a control apparatus that generates a control signal for controlling the water flow valve, based on the temperature sensed by the shell temperature detection sensor and the temperature sensed by the water temperature sensor, and outputs it to the water flow valve.

TECHNICAL FIELD

The present invention relates to a heat pump type hot-water supplyoutdoor apparatus.

BACKGROUND ART

Since a compressor of a refrigeration cycle becomes a high temperatureduring the operation, it is sometimes expected to cool the compressor(Patent Literature 1). Moreover, as a measure for the state ofrefrigerant being accumulated (called accumulation/liquefaction) in thecompressor, it is sometimes expected to heat the compressor (PatentLiterature 2).

(Cooling)

In a conventional heat pump type hot-water supply outdoor apparatus, awater jacket connected to a flow passage branching from a water circuitis twisted around a compressor. The temperature of the water jacket iscontrolled by measuring an outlet temperature of the water jacket with atemperature sensor (e.g., Patent Literature 1).

(Heating)

There is disclosed a technique wherein a heating unit using warm wateris provided at the lower part of a compressor, and the flow quantity ofwarm water to the heating unit is controlled based on a temperaturesensed by a temperature sensor that detects a shell temperature of thecompressor (e.g., Patent Literature 2).

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Unexamined Patent Publication No.    2002-372318 (page 5, FIG. 5)-   Patent Literature 2: Japanese Unexamined Patent Publication No.    2007-298254 (page 11, FIG. 1)

SUMMARY OF INVENTION Technical Problem

According to Patent Literature 1, the quantity of water inflowing to thewater jacket which is used for the compressor of the heat pump typehot-water supply outdoor apparatus is controlled based on a temperaturesensed by a temperature sensor provided at the outlet of thewater-jacket. For this reason, there is a problem that it is impossibleto control the temperature of the compressor shell according to both thetemperature of the water flowing into the water jacket and thetemperature of the compressor shell.

Further, there is another problem that when the quantity of waterinflowing to a water jacket is controlled based on only a temperature ofthe compressor shell, it is only possible to have either one of thefunctions of heating and cooling the compressor shell.

It is an object of the present invention to provide a heat pump typehot-water supply outdoor apparatus capable of controlling thetemperature of the compressor shell according to the temperature ofwater and the temperature of the compressor.

Furthermore, it is another object of the present invention to provide aheat pump type hot-water supply outdoor apparatus having a function ofswitching between heating and cooling of the compressor shell.

Solution to Problem

A heat pump apparatus according to the present invention includes

-   -   a refrigeration cycle that includes a compressor, a condenser,        an expansion valve, and an evaporator,    -   a water jacket that is arranged on a shell of the compressor and        connected in a middle of a branch path branching in parallel to        a main circuit which starts flowing from a hot water storage        tank to the condenser and returns to the hot water storage tank        from the condenser and branching at a branch located at an inlet        side of the condenser and at a branch located at an outlet side        of the condenser in the main circuit, and that lets water        flowing out from the hot water storage tank pass through the        water jacket itself,    -   a regulating valve that is connected in a middle of the branch        path between the branch at the inlet side and the water jacket,        and regulates, according to a control signal having been input,        a water flow quantity,    -   a first temperature sensor that senses a temperature of the        shell of the compressor,    -   a second temperature sensor that is installed upstream of the        regulating valve and senses a temperature of water flowing out        from the hot water storage tank, and    -   a control apparatus that generates the control signal for        controlling the regulating valve, based on the temperature        sensed by the first temperature sensor and the temperature        sensed by the second temperature sensor, and outputs the control        signal having been generated to the regulating valve.

The second temperature sensor is installed at one of positions in avicinity of the branch at the inlet side, in a vicinity of the branchpath between the branch at the inlet side and the regulating valve, andin a vicinity and upstream of the regulating valve.

The heat pump apparatus further includes a third temperature sensor thatsenses a temperature of an ambient air,

-   -   wherein the control apparatus generates the control signal,        based on the temperature sensed by the first temperature sensor,        the temperature sensed by the second temperature sensor, and the        temperature sensed by the third temperature sensor, and outputs        the control signal having been generated to the regulating        valve.

The control apparatus calculates an ambient air temperature increaserate, which indicates an increase rate of an ambient air temperature,based on the temperature sensed by the third temperature sensor, and ashell temperature increase rate, which indicates an increase rate of atemperature of the shell of the compressor, based on the temperaturesensed by the first temperature sensor, and generates a temperatureincrease rate dependent control signal, which is a second control signalfor controlling the regulating valve, based on a high-low relationbetween the ambient air temperature increase rate and the shelltemperature increase rate.

A method, according to the present invention, for controlling aregulating valve in a heat pump apparatus provided with a refrigerationcycle that includes a compressor, a condenser, an expansion valve, andan evaporator; a water jacket that is arranged on a shell of thecompressor and connected in a middle of a branch path branching inparallel to a main circuit which starts flowing from a hot water storagetank to the condenser and returns to the hot water storage tank from thecondenser and branching at a branch located at an inlet side of thecondenser and at a branch located at an outlet side of the condenser inthe main circuit, and that lets water flowing out from the hot waterstorage tank pass through the water jacket itself, the regulating valvethat is connected in a middle of the branch path between the branch atthe inlet side and the water jacket, and, by being controlled, regulatesa water flow quantity, a first temperature sensor that senses atemperature of the shell of the compressor, and a second temperaturesensor that is installed upstream of the regulating valve and senses atemperature of water flowing out from the hot water storage tank, themethod includes

-   -   controlling, by a control apparatus, the regulating valve based        on the temperature sensed by the first temperature sensor and        the temperature sensed by the second temperature sensor.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a heatpump type hot-water supply outdoor apparatus that can control thetemperature of the compressor, based on the water temperature of a watercircuit and the temperature of the compressor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a configuration diagram of a heat pump type hot-watersupply outdoor apparatus 1 a according to Embodiment 1;

FIG. 2 shows a hardware structure of a control apparatus 20 a accordingto Embodiment 1;

FIG. 3 shows a control by the control apparatus 20 a according toEmbodiment 1;

FIG. 4 is a flowchart showing a heating control of a compressor 2 by thecontrol apparatus 20 a according to Embodiment 1;

FIG. 5 is a flowchart showing a cooling control of the compressor 2 bythe control apparatus 20 a according to Embodiment 1;

FIG. 6 shows an installation position of a water temperature sensoraccording to Embodiment 1; and

FIG. 7 shows a configuration diagram of a heat pump type hot-watersupply outdoor apparatus 1 b according to Embodiment 2.

DESCRIPTION OF EMBODIMENTS Embodiment 1

FIG. 1 shows a configuration diagram of a heat pump type hot-watersupply outdoor apparatus 1 a (heat pump apparatus) according toEmbodiment 1.

(Refrigerant Circuit Side)

As shown in FIG. 1, the refrigerant circuit side, through whichrefrigerant circulates, starts from the discharge side of a compressor2, passes through a water-refrigerant heat exchanger 3 (condenser), anexpansion valve 4, and an air heat exchanger 5 (evaporator), andconnects to the inlet side of the compressor 2. The refrigeration cycleincludes the compressor 2, the water-refrigerant heat exchanger 3, theexpansion valve 4, and the air heat exchanger 5.

(Water Circuit Side)

The water circuit side, through which a circulating pump 40 circulateswater, configures a main water circuit 7 (main circuit) that starts froma hot water storage tank 30, passes through the water-refrigerant heatexchanger 3, and returns to the hot water storage tank 30. That is, themain water circuit 7 flows into the water-refrigerant heat exchanger 3from the hot water storage tank 30, and flows out of thewater-refrigerant heat exchanger 3 to return to the hot water storagetank 30.

(Branch Water Circuit)

As shown in FIG. 1, a branch water circuit 8 (branch path) is connectedin parallel to the main water circuit 7. Before flowing to thewater-refrigerant heat exchanger 3 from the main water circuit 7, thebranch water circuit 8 branches from the main water circuit 7. That is,the branch water circuit 8 branches in parallel to the main watercircuit 7, at the branch A at the inlet side of the water-refrigerantheat exchanger 3 and at the branch B at the outlet side of it. Thebranch water circuit 8 branches from the main water circuit 7 at thebranch A before the flow into the water-refrigerant heat exchanger 3,and, through a water flow valve 9 and a water jacket 10, joins the mainwater circuit 7 having flowed out of the water-refrigerant heatexchanger 3 at the branch B.

(Structure of Heat Pump Type Hot-Water Supply Outdoor Apparatus 1 a)

The heat pump type hot-water supply outdoor apparatus 1 a is providedwith the refrigeration cycle, which includes the compressor 2, thewater-refrigerant heat exchanger 3, the expansion valve 4, and the airheat exchanger 5, the water flow valve 9 (regulating valve), the waterjacket 10, a shell temperature detection sensor 6 (first sensor), awater temperature sensor 11 (second sensor), and a control apparatus 20a.

(1) The water jacket 10 is connected in the middle of the branch watercircuit 8, and arranged on the shell of the compressor 2. Water flowingfrom the hot water storage tank 30 passes through a water flow passageformed inside the water jacket 10.

(2) The water flow valve 9 is connected in the middle of the branchwater circuit 8, between the inlet side branch A and the water jacket10, and regulates the quantity of water flow, according to an inputcontrol signal from the control apparatus 20 a.

(3) The shell temperature detection sensor 6 senses a temperature of theshell of the compressor 2.

(4) The water temperature sensor 11, installed upstream of the waterflow valve 9 and before the main water circuit 7 flowing into thewater-refrigerant heat exchanger 3, senses a temperature of the waterflowing out of the hot water storage tank 30 (water before inflowing tothe water-refrigerant heat exchanger 3). FIG. 1 shows the case in whichthe water temperature sensor 11 is installed in the vicinity of thebranch A at the inlet side of the water-refrigerant heat exchanger 3.

(5) The control apparatus 20 a generates a control signal forcontrolling the water flow valve 9, based on temperatures sensed by theshell temperature detection sensor 6 and the water temperature sensor11, and outputs the control signal to the water flow valve 9.

(Hardware Structure of Control Apparatus 20 a)

FIG. 2 shows a hardware structure of the control apparatus 20 a. In FIG.2, the control apparatus 20 a includes a CPU 810 (Central ProcessingUnit) which executes programs. The CPU 810 is connected via a bus 825 toa ROM (Read Only Memory) 811, a RAM (Random Access Memory) 812, and anI/F (Interface) unit 816, and controls these hardware devices.

The ROM 811 is an example of a nonvolatile memory. In the ROM 811, thereare stored programs that execute functions of the control apparatus 20 aand set values T₁, T₂, etc. that are to be described later. The programsof the ROM 811 are read out and executed by the CPU 810. The RAM 812 isan example of a volatile memory. In the RAM 812, there are storedtemperatures sensed by the shell temperature detection sensor 6 and thewater temperature sensor 11, a control signal to be transmitted to thewater flow valve 9, information on “judgment result”, “calculationresult”, “generation result”, “processing result”, etc. performed by theCPU 810, data, signal values, variable values, parameters, etc. The ROM811 and the RAM 812 are examples of a storage device or a storage unit.

The I/F unit 816 is an example of a communication unit. The I/F unit 816is connected to the water flow valve 9, the shell temperature detectionsensor 6, the water temperature sensor 11, etc.

(Operations of Heat Pump Type Hot-Water Supply Outdoor Apparatus 1 a)

Now, with reference to FIG. 1, the operation of the heat pump typehot-water supply outdoor apparatus 1 a will be described.

(Flow of Refrigerant)

In the heat pump type hot-water supply outdoor apparatus 1 a, hightemperature refrigerant 51 discharged from the compressor 2 flows intothe water-refrigerant heat exchanger 3. After giving heat to lowtemperature water 61 of the main water circuit 7, the high temperaturerefrigerant 51, as low temperature refrigerant 52, passes through theexpansion valve 4 and the air heat exchanger 5, and returns to the inletside of the compressor 2.

(Flow of Water)

As the movement of the water side, the low temperature water 61 flowingfrom the hot water storage tank 30 by the circulating pump 40 flows intothe water-refrigerant heat exchanger 3, and since the temperature of thewater increases by performing heat exchange with the high temperaturerefrigerant 51, becomes high temperature water 62 whose temperature ishigher than that of the low temperature water 61 and returns to the hotwater storage tank 30.

The brief summary of the basic operation of the heat pump type hot-watersupply outdoor apparatus 1 a is the following two points:

(Basic Operation 1: Heating of Compressor 2)

First, when a temperature T(11) sensed by the water temperature sensor11 is higher than a temperature T(6) sensed by the shell temperaturedetection sensor 6, that is when

T(6)<T(11)  (Expression 1),

the control apparatus 20 a opens the water flow valve 9 in order to flowwater through the water jacket 10. The compressor 2 is heated due toletting the water flow through the water jacket 10. That is, the controlapparatus 20 a inputs temperatures (detection signals) sensed by theshell temperature detection sensor 6 and the water temperature sensor11, and compares T(6) with T(11). Then, if it is judged that T(6)<T(11),the control apparatus 20 a generates a control signal indicating to openthe water flow valve 9 and outputs it to the water flow valve 9.

Thus, by warming the compressor 2 by the heat of the water, it ispossible to prevent accumulation/liquefaction of the refrigerant in thecompressor 2 and improve rising capacity in the state of a low ambientair temperature.

(Basic Operation 2: Cooling of Compressor 2)

On the other hand, when the temperature T(11) sensed by the watertemperature sensor 11 is lower than the temperature T(6) sensed by theshell temperature detection sensor 6, that is when

T(6)>T(11)  (Expression 2),

the compressor 2 is cooled due to opening the water flow valve 9 to letthe water flow through the water jacket 10. That is, the controlapparatus 20 a inputs temperatures (detection signals) sensed by theshell temperature detection sensor 6 and the water temperature sensor11, and compares T(6) with T(11). Then, if it is judged that T(6)>T(11),the control apparatus 20 a generates a control signal indicating to openthe water flow valve 9 and outputs it to the water flow valve 9.

In the case of the basic operation 2, it is possible to effectivelycollect heat loss of the compressor 2 by making the heat loss from thecompressor 2 be absorbed by water so as to return it to the main watercircuit 7. Moreover, without a special protective device, it is possibleto prevent the compressor 2 from becoming extraordinarily overheated.

The control apparatus 20 a does not apply the Expressions 1 and 2 asthey are. The Expressions 1 and 2 only show the outline of controllingheating and cooling of the compressor 2 performed by the controlapparatus 20 a. If the Expressions 1 and 2 are applied as they are, thecontrol apparatus 20 a would provide control to close the water flowvalve 9 only when T(6)=T(11), and provide control to open the water flowvalve 9 when other than the above. Specifically, the control apparatus20 a performs the following control, for example.

Even when temperatures sensed by the sensors satisfy T(6)<T(11) of theExpression 1, it may be acceptable not to open the water flow valve 9(when not expecting to heat the compressor by the water any more) if thetemperature sensed by the shell temperature detection sensor 6 isgreater than or equal to a certain set value T₁. That is, when thetemperature sensed by the shell temperature detection sensor 6 isgreater than or equal to the certain temperature T₁, namely when

T₁≦T(6)<T(11)  (Expression 3),

the water flow valve 9 is not opened since it is not necessary to warmthe compressor 2.

In contrast, even when T(6)>T(11) is satisfied, it may be acceptable notto open the water flow valve 9 (when not expecting to cool thecompressor by the water any more) if the temperature sensed by the shelltemperature detection sensor 6 is less than or equal to a certain setvalue T₂. That is, when

T₂≧T(6)>T(11)  (Expression 4),

the water flow valve 9 is not opened since it is not necessary to coolthe compressor 2.

FIG. 3 typically shows the cases of Expressions 3 and 4. The arrowindicates a temperature T. (a) of FIG. 3 shows the Expression 3. Thatis, when T(6) is greater than or equal to the set value T₁, even ifT(6)<T(11) is satisfied, the control apparatus 20 a does not open thewater flow valve 9. (b) of FIG. 3 shows the Expression 4. That is, whenT(6) is less than or equal to the set value T₂, even if T(6)>T(11) issatisfied, the control apparatus 20 a does not open the water flow valve9.

(c) of FIG. 3 is a schematic diagram of the case where Expressions 3 and4 are reflected in the control performed by the control apparatus 20 a.

(Range of T₁≦T(6)≦T₂)

When T(6) is in the range of T₁≦T(6)≦T₂, the control apparatus 20 akeeps the water flow valve 9 closed regardless of the value of T(11).

(Range of T(6)<T₁)

When T(6)<T₁, the compressor 2 needs to be heated. Therefore, under thiscondition, if T(6)<T(11) is further satisfied, the control apparatus 20a controls the water flow valve 9 to open.

If T(6)>T(11), since it is impossible to heat the compressor 2 by usingthe water flow, the control apparatus 20 a controls the water flow valve9 to close.

(Range of T(6)>T₂)

When T(6)>T₂, the compressor 2 needs to be cooled. Therefore, ifT(6)>T(11) is further satisfied, the control apparatus 20 a controls thewater flow valve 9 to open.

If T(6)<T(11), since it is impossible to cool the compressor 2 by usingthe water flow, the control apparatus 20 a controls the water flow valve9 to close.

Furthermore, with reference to FIGS. 4 and 5, controlling thetemperature of the compressor 2 performed by the control apparatus 20 ashown in FIG. 3 will be described.

FIG. 4 shows a flowchart of heating the compressor 2 in order to preventaccumulation/liquefaction of the refrigerant, when starting theoperation of the compressor 2.

FIG. 5 shows a flowchart of cooling the compressor 2 in order to preventoverheating of the compressor 2, while the compressor 2 is in operation.

In FIGS. 4 and 5, before starting the control performed by the controlapparatus 20 a, it is supposed that the water flow valve 9 is closed.

(Heating of Compressor 2)

First, with reference to FIG. 4, there will be explained the case ofheating the compressor 2 by the control apparatus 20 a when starting theoperation of the compressor 2. The brief summary of FIG. 4 is asfollows: In the case of a sensed temperature T(6) (hereinafter alsocalled a shell temperature) sensed by the shell temperature detectionsensor 6 being lower than a set value T₁ (in the case of the compressor2 being cold), the shell temperature T(6) is further compared with asensed temperature T(11) (hereinafter also called a sensed watertemperature) sensed by the water temperature sensor 11. Since it ispossible to perform heating when the sensed water temperature T(11) ishigher than the shell temperature T(6), the water flow valve 9 is openedto heat the compressor 2. Then, when the shell temperature T(6) exceedsa “set value T+α”, the water flow valve 9 is closed (heating isstopped). The flowchart of FIG. 4 will now be explained.

In S101, the compressor 2 shall be in a stopped condition and the waterflow valve 9 shall be closed.

In S102, the control apparatus 20 a starts to control the water flow ofthe water jacket 10. By this control, it is possible to prevent thestate (accumulation/liquefaction of refrigerant) in which refrigerant ofthe refrigeration cycle melts, as liquid refrigerant, into refrigerantoil of the compressor 2 in a stopped condition.

In S103, the control apparatus 20 a compares a shell temperature T(6)with a set value T₁ (e.g., 5° C.). Since it is not necessary to performheating when the shell temperature T(6)≧the set value T₁, the controlapparatus 20 a keeps the water flow valve 9 closed (S109).

On the other hand, since it is necessary to perform heating when theshell temperature T(6)<the set value T₁, the control apparatus 20 acompares the shell temperature T(6) with a sensed water temperatureT(11) in order to judge whether heating can be performed by using thewater flow or not (S104).

Since it is impossible to perform heating when the shell temperatureT(6)≧the sensed water temperature T(11), the control apparatus 20 akeeps the water flow valve 9 closed (S110).

On the other hand, since it is possible to perform heating when theshell temperature T(6)<the sensed water temperature T(11), the controlapparatus 20 a controls the water flow valve 9 to open (S105).

In S106, the control apparatus 20 a compares the shell temperature T(6)with a “set value T₁+α” (e.g., T₁=5° C., α=5° C.). That is, the controlapparatus 20 a judges whether the compressor 2 has been heated up to therequired temperature “set value T₁+α” (10° C.) or not. When the shelltemperature T(6) exceeds the “set value T₁+α” (judging that heating iscompleted), the control apparatus 20 a provides control to close thewater flow valve 9 (S107) to finish the control processing (S108).

(Cooling of Compressor 2)

Next, with reference to FIG. 5, there will be explained the case ofcooling the compressor 2 by the control apparatus 20 a while thecompressor 2 is in operation. The brief summary of FIG. 5 is as follows:In the case of a shell temperature T(6) being higher than a set value T₂(in the state of the compressor 2 being overheated), the shelltemperature T(6) is further compared with a sensed water temperatureT(11) detected by the water temperature sensor 11. Since it is possibleto perform cooling when the sensed water temperature T(11) is lower thanthe shell temperature T(6), the water flow valve 9 is opened to cool thecompressor 2. Then, when the shell temperature T(6) becomes less than a“set value T₂+β”, the water flow valve 9 is closed (cooling is stopped).The flowchart of FIG. 5 will now be explained.

In S201, the compressor 2 shall be in operation and the water flow valve9 shall be closed.

In S202, the control apparatus 20 a starts to control the water flow ofthe water jacket 10. The compressor 2 in operation is prevented frombeing overheated by this control.

In S203, the control apparatus 20 a compares a shell temperature T(6)with a set value T₂ (e.g., 90° C.). Since it is not necessary to performcooling when the shell temperature T(6)≦the set value T₂, the controlapparatus 20 a keeps the water flow valve 9 closed (S209).

On the other hand, since it is necessary to perform cooling when theshell temperature T(6)>the set value T₂, the control apparatus 20 acompares the shell temperature T(6) with a sensed water temperatureT(11) in order to judge whether cooling can be performed by using thewater flow or not (S204).

Since it is impossible to perform cooling when the shell temperatureT(6)≦the sensed water temperature T(11), the control apparatus 20 akeeps the water flow valve 9 closed (S210).

On the other hand, since it is possible to perform cooling when theshell temperature T(6)>the sensed water temperature T(11), the controlapparatus 20 a controls the water flow valve 9 to open (S205).

In S206, the control apparatus 20 a compares the shell temperature T(6)with a “set value T₂+β” (e.g., T₂=90° C., β=−10° C.). That is, thecontrol apparatus 20 a judges whether the compressor 2 has been cooleddown to the required temperature “set value T₂+β” (80° C.) or not. Whenthe shell temperature T(11) becomes less than the “set value T₂+β”(judging that cooling is completed), the control apparatus 20 a providescontrol to close the water flow valve 9 (S207) to finish the controlprocessing (S208).

(Installation Position of Water Temperature Sensor 11)

With reference to FIG. 6, an installation position of the watertemperature sensor 11 will be explained. FIG. 6 shows the installationposition of the water temperature sensor 11. Although FIG. 1 shows thecase in which the water temperature sensor 11 is installed in thevicinity of the branch A at the inlet side of the water-refrigerant heatexchanger 3, since what is needed for the water temperature sensor 11 isonly to sense a temperature of water before inflowing to thewater-refrigerant heat exchanger 3, it is also preferable to install thewater temperature sensor, as shown in FIG. 6 as a water temperaturesensor 11-1, to be in the vicinity of the branch water circuit 8 betweenthe branch A at the inlet side of the water-refrigerant heat exchanger 3and the water flow valve 9. Alternatively, as shown as a watertemperature sensor 11-2, the water temperature sensor may be installedto be upstream of and in the vicinity of the water flow valve 9, in thebranch water circuit 8.

As described above, the control apparatus 20 a judges to control thewater flow valve 9 for flowing water to the water jacket 10, based ontemperatures sensed by the shell temperature detection sensor 6 and thewater temperature sensor 11. Therefore, depending on the compressor 2(temperature of the compressor 2) and the water temperature, it ispossible to collect useless heat loss from the compressor 2 or to reduceelectric power for keeping the compressor 2 warm (to reduce standbyelectricity). The shell temperature detection sensor 6 is a sensororiginally existing for controlling the refrigerant, and the watertemperature sensor 11 is a sensor originally existing for controllingthe temperature of hot water to be supplied. Thus, the above-describedeffect can be obtained without the time and effort to add sensors andcost increase caused by adding the sensors.

Embodiment 2

With reference to FIG. 7, a heat pump type hot-water supply outdoorapparatus 1 b according to Embodiment 2 will be described. Compared withthe heat pump type hot-water supply outdoor apparatus 1 a of Embodiment1, the heat pump type hot-water supply outdoor apparatus 1 b ofEmbodiment 2 further includes an ambient air temperature sensor 12(third temperature sensor) that senses an ambient air temperature.

In Embodiment 1, the control apparatus 20 a judges to control the waterflow valve 9, based on temperatures sensed by the shell temperaturedetection sensor 6 and the water temperature sensor 11. In Embodiment 2,a control apparatus 20 b also uses a temperature sensed by the ambientair temperature sensor 12.

FIG. 7 shows a configuration diagram of the heat pump type hot-watersupply outdoor apparatus 1 b according to Embodiment 2. FIG. 7 differsfrom FIG. 1 of Embodiment 1 in that the ambient air temperature sensor12 is arranged. Thereby, the function of the control apparatus 20 bslightly differs from that of the control apparatus 20 a. That is, thecontrol apparatus 20 b judges to control the water flow valve 9 forflowing water to the water jacket 10, based on three types oftemperatures sensed by the shell temperature detection sensor 6, thewater temperature sensor 11, and the ambient air temperature sensor 12.That is, the control apparatus 20 b generates a signal for controllingthe water flow valve 9, based on the temperatures sensed by the threetypes of sensors, and outputs it to the water flow valve 9.

In addition to the generation of the control signal of Embodiment 1, thecontrol apparatus 20 b generates a control signal (a temperatureincrease rate dependent control signal) described below, and outputs itto the water flow valve 9. That is, when an increase rate per unit timeof an ambient air temperature (sensed by the ambient air temperaturesensor 12) is faster than that of the shell temperature of thecompressor 2 (sensed by the shell temperature detection sensor 6), thecontrol apparatus 20 b judges that there is a large amount ofaccumulation/liquefaction of refrigerant in the compressor 2, generatesa control signal indicating to open the water flow valve 9, and outputsit to the water flow valve 9. That is, in such a case, regardless ofhigh or low of the sensed temperature, the increase rate (speed) of eachsensed temperature is subject to judgment.

By this control, the heat pump type hot-water supply outdoor apparatushaving higher reliability can be provided. In addition, since theambient air temperature sensor 12 is also a sensor originally existing,the above-described effect can be obtained without adding sensors andcost increase caused by adding the sensors.

Furthermore, specific explanation will be described. Refrigerantaccumulation/liquefaction occurs only when the compressor 2 is in astopped condition. If the compressor 2 begins to operate in the statewhere the refrigerant has accumulated and liquefied while the compressor2 has been stopped (the state where lubricating oil in the compressorhas been diluted by the refrigerant), seizure etc. occurs due to poorlubrication of the sliding part of the compressor 2. While thecompressor is in a stopped condition, the refrigerant in the refrigerantcircuit tends to be collected and condensed as liquid(accumulation/liquefaction) at the portion of the lowest temperature inthe refrigerant circuit. When the shell temperature of the compressor 2is low, though it is certain that refrigerant is easilyaccumulated/liquefied in the compressor 2, it is not an absolute value,in a precise sense, of the compressor shell temperature. Refrigeranttends to collect at a part, in each part of the refrigerant circuit,having a temperature increase rate slower than that of the ambient airtemperature (surrounding temperature) because the part is colder at thetime. Note that this phenomenon occurs while the compressor 2 is in astopped condition. Generally, since the compressor 2 has a high heatcapacity (difficult to warm) in the parts of the refrigerant circuit,refrigerant becomes collected (accumulated/liquefied) in the compressor2. Therefore, when a difference between the increase rate of the ambientair temperature and that of the shell temperature of the compressor 2can be sensed by dint of adding the ambient air temperature sensor 12,it becomes possible to judge whether it is in the state whereaccumulation/liquefaction of the refrigerant easily occurs in thecompressor 2 or not. That is, according to Embodiment 2, the controlapparatus 20 b firstly compares the temperature variation range per unittime of the ambient air temperature and that of the compressor shelltemperature. When the variation range in the direction of temperatureincrease of the ambient air temperature is larger than that of the shelltemperature of the compressor 2, namely when the temperature increaserate of the ambient air temperature>the temperature increase rate of thecompressor shell, since it can be judged that possibility of refrigerantaccumulation/liquefaction in the compressor 2 is high (the range inwhich heating should be performed), the control apparatus 20 b controlsthe water flow valve 9 to open. However, with regard to the temperatureT(6) sensed by the shell temperature detection sensor 6 and thetemperature T(11) sensed by the water temperature sensor 11, whenT(6)>T(11), it is impossible to heat the compressor 2 even if the waterflow valve 9 is opened. Therefore, in such a case, the control apparatus20 b provides control to close the water flow valve 9.

According to Embodiment 1, since the water temperature in the hot waterstorage tank 30 may be affected (temperature decrease) by letting waterflow through the water jacket 10, and since there may a need forincreasing output of the circulating pump 40 in order to let water flowthrough the water jacket 10 (in order to overcome the flow passageresistance), power consumption may increase as the whole system. Then,in such a case, the accuracy of judging whether it is in the state ofrefrigerant accumulation/liquefaction being likely to occur in thecompressor 2 or not can be enhanced by adding the ambient airtemperature sensor 12 compared with the case of using the two sensors ofthe shell temperature detection sensor 6 and the water temperaturesensor 11. Thereby, it is possible to inhibit the influence on the watertemperature in the hot water storage tank 30, and to inhibit theincrease of power consumption of the circulating pump 40.

In Embodiments 1 and 2, the water flow valve 9 is explained as a stopvalve which performs opening or closing. This however describes anexample, and the function of the water flow valve 9 may be the onecapable of regulating the quantity of water flow in multiple stages. Thecontrol apparatus 20 a (or the control apparatus 20 b) generates andoutputs control signals responsive to the multiple stages, based ontemperatures sensed by the sensors. The type of a control signal to begenerated is programmed in advance. Moreover, the function of the waterflow valve 9 may be the one capable of continuously regulating thequantity of water flow. Also, in that case, the control apparatus 20 a(or the control apparatus 20 b) generates and outputs a control signalresponsive to the continuous regulating, based on temperatures sensed bythe sensors. The type of a control signal to be generated is programmedin advance.

Although the heat pump apparatus is explained in Embodiments 1 and 2, itis also acceptable to comprehend the heat pump apparatus as a regulatingvalve control method by which a control apparatus controls a water flowvalve (regulating valve). That is, with regard to a heat pump apparatusprovided with a refrigeration cycle including a compressor, a condenser,an expansion valve, and an evaporator, the water jacket 10, the waterflow valve 9 connected in the middle of the branch path between thebranch at the inlet side and the water jacket and controlled accordingto an input control signal, the shell temperature detection sensor 6,and the water temperature sensor 11, it is possible to comprehend theheat pump apparatus as a regulating valve control method by which acontrol apparatus controls the water flow valve 9, based on thetemperatures sensed by the shell temperature detection sensor 6 and thewater temperature sensor 11.

REFERENCE SIGNS LIST

1 a, 1 b Heat pump type hot-water supply outdoor apparatus, 2Compressor, 3 Water-refrigerant heat exchanger, 4 Expansion valve, 5 Airheat exchanger, 6 Shell temperature detection sensor, 7 Main watercircuit, 8 Branch water circuit, 9 Water flow valve, 10 Water jacket, 11Water temperature sensor, 12 Ambient air temperature sensor, 20 a, 20 bControl apparatus, 30 Hot water storage tank, 40 Circulating pump

1. A heat pump apparatus comprising: a refrigeration cycle that includesa compressor, a condenser, an expansion valve, and an evaporator; awater jacket that is arranged on a shell of the compressor and connectedin a middle of a branch path branching in parallel to a main circuitwhich starts flowing from a hot water storage tank to the condenser andreturns to the hot water storage tank from the condenser and branchingat a branch located at an inlet side of the condenser and at a branchlocated at an outlet side of the condenser in the main circuit, and thatlets water flowing out from the hot water storage tank pass through thewater jacket itself; a regulating valve that is connected in a middle ofthe branch path between the branch at the inlet side and the waterjacket, and regulates, according to a control signal having been input,a water flow quantity; a first temperature sensor that senses atemperature of the shell of the compressor; a second temperature sensorthat is installed upstream of the regulating valve and senses atemperature of water flowing out from the hot water storage tank; and acontrol apparatus that generates the control signal for controlling theregulating valve, based on the temperature sensed by the firsttemperature sensor and the temperature sensed by the second temperaturesensor, and outputs the control signal having been generated to theregulating valve.
 2. The heat pump apparatus according to claim 1,wherein the second temperature sensor is installed at one of positionsin a vicinity of the branch at the inlet side, in a vicinity of thebranch path between the branch at the inlet side and the regulatingvalve, and in a vicinity and upstream of the regulating valve.
 3. Theheat pump apparatus according to claim 1, further comprising a thirdtemperature sensor that senses a temperature of an ambient air, whereinthe control apparatus generates the control signal, based on thetemperature sensed by the first temperature sensor, the temperaturesensed by the second temperature sensor, and the temperature sensed bythe third temperature sensor, and outputs the control signal having beengenerated to the regulating valve.
 4. The heat pump apparatus accordingto claim 3, wherein the control apparatus calculates an ambient airtemperature increase rate, which indicates an increase rate of anambient air temperature, based on the temperature sensed by the thirdtemperature sensor, and a shell temperature increase rate, whichindicates an increase rate of a temperature of the shell of thecompressor, based on the temperature sensed by the first temperaturesensor, and generates a temperature increase rate dependent controlsignal, which is a second control signal for controlling the regulatingvalve, based on a high-low relation between the ambient air temperatureincrease rate and the shell temperature increase rate.
 5. A method forcontrolling a regulating valve in a heat pump apparatus provided with arefrigeration cycle that includes a compressor, a condenser, anexpansion valve, and an evaporator; a water jacket that is arranged on ashell of the compressor and connected in a middle of a branch pathbranching in parallel to a main circuit which starts flowing from a hotwater storage tank to the condenser and returns to the hot water storagetank from the condenser and branching at a branch located at an inletside of the condenser and at a branch located at an outlet side of thecondenser in the main circuit, and that lets water flowing out from thehot water storage tank pass through the water jacket itself, theregulating valve that is connected in a middle of the branch pathbetween the branch at the inlet side and the water jacket, and, by beingcontrolled, regulates a water flow quantity, a first temperature sensorthat senses a temperature of the shell of the compressor, and a secondtemperature sensor that is installed upstream of the regulating valveand senses a temperature of water flowing out from the hot water storagetank, the method comprising: controlling, by a control apparatus, theregulating valve based on the temperature sensed by the firsttemperature sensor and the temperature sensed by the second temperaturesensor.
 6. The heat pump apparatus according to claim 2, furthercomprising a third temperature sensor that senses a temperature of anambient air, wherein the control apparatus generates the control signal,based on the temperature sensed by the first temperature sensor, thetemperature sensed by the second temperature sensor, and the temperaturesensed by the third temperature sensor, and outputs the control signalhaving been generated to the regulating valve.
 7. The heat pumpapparatus according to claim 6, wherein the control apparatus calculatesan ambient air temperature increase rate, which indicates an increaserate of an ambient air temperature, based on the temperature sensed bythe third temperature sensor, and a shell temperature increase rate,which indicates an increase rate of a temperature of the shell of thecompressor, based on the temperature sensed by the first temperaturesensor, and generates a temperature increase rate dependent controlsignal, which is a second control signal for controlling the regulatingvalve, based on a high-low relation between the ambient air temperatureincrease rate and the shell temperature increase rate.